【作者】 杨游；

【导师】 宋代军；

【作者基本信息】 西南农业大学 ， 动物营养与饲料科学， 2004， 硕士

【摘要】 本试验旨在研究尿素添加水平、水分含量、时间对氨化秸秆营养价值的影响，以确定氨化稻草秸秆尿素、水分、时间处理参数的优化组合。同时，根据不同处理条件下秸秆纤维组分和显微结构的变化，对氨化机理进行探讨。 试验采用二次通用旋转回归组合设计，以未处理秸秆为对照，研究尿素（占秸秆干物质含量的2.0％、3.0％、4.5％、6.0％、7.0％）、水分（10g、16g、25g、34g、40g）、时间（12d、18d、27d、36d、42d）三因素五水平20种不同配比组合的NDF、ADF、CEL、ADL纤维成分、CP含量，TSM-2型扫描电镜下显微结构以及山羊瘤胃内DM、NDF、ADF的48h消失率变化，从而确定各因素对NDF、ADF、CEL、ADL纤维成分、CP含量、显微结构、D_DM48、D_NDF48、D_ADF48的影响。根据二次通用旋转回归模式，建立尿素、水分、时间对NDF、ADF、CEL、ADL、D_DM48、D_NDF48、D_ADF48的回归模型，并对回归模型进行优化分析及参数优化。 试验结果表明：（1）稻草秸秆经尿素氨化处理后，NDF、ADF、CEL、ADL纤维成分含量降低，CP含量提高，瘤胃内D_DM48、D_NDF48、D_ADF48提高。说明尿素氨化能改善秸秆的营养价值。（2）秸秆NDF、ADF、CEL、ADL纤维成分含量随尿素添加水平的增加而降低（P＜0.05），CP含量随尿素的增加而增加（P＜0.01）。随处理时间的延长，氨化后CP含量呈递增，NDF、ADF、CEL及ADL的含量呈下降趋势（P＞0.05）。水分的降低对NDF、ADF含量降低的效果不显著（P＞0.05），而对CEL、ADL含量在一些组间差异显著（P＜0.05），在一些组间差异不显著（P＞0.05）；氨化后CP的含量随水分的增加而减小（P＜0.01）。（3）尿素对稻草秸秆在山羊瘤胃内48h消化率的影响起主导作用（0.05＜P＜0.10），尿素添加水平在6.0％时，D_DM48、D_NDF48、D_ADF48达到最大，低尿素水平组2.0％D_DM48、D_ADF48最低。水分及时间对氨化秸杆的48h消化率的影响较小（P＞0.05）。（4）尿素氨化对稻草秸秆的结构产生影响。稻草秸杆经氨化处理后稻草表面呈光滑的纤维状且孔隙率增多，以致稻草吸附纤维素酶的表面积增大，从而有助于纤维素的利用及酶解的进行。此外，秸秆表面的孔隙随尿素浓度的增加而增多，而时间、水分对秸秆显微结构的影响较小。（5）根据试验结果及回归方程分析，综合各试验指标的各优化参数组合，认为尿素氨化稻草秸秆在本试验条件下的参数优化组合为：尿素7.0％，水分10％，时间12d。更多还原

【Abstract】 This experiment was designed to study the influence of various levels of urea, moisture and reaction time on the nutrition value of rice straw ammoniated, so as to determine the optimal parameters of urea, moisture and time of ammoniation . Moreover, by analyzing the changes of microstructure and fiber content of rice straw ammoniated, the mechanism of ammoniation was discussed.By the quadratic general rotary unitized design, compared with untreated sample, twenty combinations of three factors and five levels were studied the changes of the fiber content of NDF, ADF, CEL and ADL, CP content, microstructure and the 48 hour digestibility of DM, NDF, ADF in goat’s rumen.The purpose was to analyze the relation between every factor and the nutrition of rice straw ammoniated. Five levels of urea selected in this experiment were 2.0%, 3.0%, 4.5%, 6.0%, 7.0% dry matter, moisture were 10g, 16g, 25g, 34g, 40g,reaction time were 12d, 18d, 27d, 36d, 42d.According to the quadratic general rotary unitized design, the regression models of urea, moisture, time and NDF, ADF, CEL, ADL, CP, DDM48,DNDF48,DADF48 were set up and parameters were optimized.Results showed:(1) When rice straw were ammoniated, all treatments’fiber content of NDF, ADF, CEL, ADL decreased, the CP content increased, the 48 hour digestibility of DM, NDF, ADF in goat’s rumen increased. The result approved that ammoniation can improve the nutrition value of rice straw. (2) With the increasing of the levels of urea, the fiber content of NDF, ADF, CEL, ADL decreased (P<0.05) , the CP content increased (P<0.01) .With the prolong of reaction time ,the CP content increased, the fiber content of NDF, ADF, CEL, ADL decreased ,but the difference was not significant (P>0.05) .With the decreasing of moisture , the decreasing difference of NDF, ADF was not significant (P>0.05) ,the decreasing difference of CEL, ADL was significant in some groups and was not in the others groups, the CP content decreased (P<0.01) .(3)The influence of urea levels on the 48 hour digestibility of rice straw in goat’s rumen was primary. DDM48, DNDF48, DADF48 of 6.0% urea were the biggest and they were the smallest at 2.0%urea. The influence of moisture and reaction time on the 48 hour digestibility of rice straw in goat’s rumen is minor ( P>0.05 ) .(4) Ammoniation changed the microstructure of rice straw: the microstructural surfaces of rice straw treated by urea presented smooth fibriform and their holes increased. This change would lead to the area of rice straw easily absorb cellulose enzyme , which maked for the utilization of cellulose and the seperation of enzyme. In addition, with the levels of urea enhancing, these holes increased, but they decreased with the levels of moisture and time increasing. (5)According to the results of experiment and the analysis of regression model, and summarizing various optimum parameters of every testing item, the optimum parameters(urea 7.0%, moisture 10%, reaction time 12d) of rice straw treated by urea were determined in this testing condition.更多还原